1. Field of the Invention
This invention relates to a sealing material which is disposed in a cavity of a pillar or another member in an automobile and heated for foaming into a polyurethane foam with which the cavity is filled and a method for providing a seal using the same.
2. Prior Art
Automobile center pillars and other frame members have a hollow cavity. Common practice is to fill the cavity with a foam for the purposes of preventing wind noise and absorbing vibration. The cavity is filled with a foam by various methods. For example, foam previously shaped to the cavity shape is inserted into the cavity through an access opening. Alternatively, a foamable material which is capable of foaming and expanding upon heating is placed in the cavity as a spot sealing material and later foamed to fill the cavity by heat encountered in a furnace for baking electrodeposited paint coating.
The former method of inserting a shaped foam body into a cavity, however, has the problem that the cavity is filled to a varying extent partially because of insertion through an access opening. It is difficult to completely fill the cavity along its configuration from corner to corner. The access opening which is often defined by punching out strip steel is dangerous in that the worker would have his hands injured.
The latter method also suffers from several problems. Sealing materials known as spot sealing material generally have, at most, a blowing size twice as large as what it was. Where a large volume must be filled, a large amount of sealing material is needed, which increases not only the cost, but also the weight against the general demand of lightweight automobiles.